How much concrete do I need for a slab?

To calculate concrete needed for a slab, multiply length × width × thickness. For a 10ft × 10ft × 4-inch slab, you need approximately 1.23 cubic yards. Our calculator automatically includes the 10% waste factor.

How many bags of concrete do I need calculator?

The number of bags depends on your slab size and bag weight. For example, an 80lb bag covers about 0.44 cubic yards. A 10×10×4 inch slab would need approximately 3 bags of 80lb concrete mix.

How to calculate cubic yards of concrete?

Convert all measurements to feet first. Then use: Cubic Yards = (Length × Width × Thickness in feet) ÷ 27. For inches, divide thickness by 12 to convert to feet before calculating.

What is the concrete calculator formula?

Basic formula: Volume = L × W × T. For imperial units: Cubic Yards = (Length ft × Width ft × Thickness in) ÷ 324. For metric: Cubic Meters = (Length m × Width m × Thickness cm) ÷ 100.

How much does concrete cost per yard?

Bagged concrete typically costs $6-8 per 80lb bag, covering about 0.44 cubic yards each. Ready-mix concrete costs $100-150 per cubic yard. Our calculator compares different bag sizes for the best value.

How to calculate concrete bags needed?

First calculate your volume in cubic yards, then divide by the coverage per bag. An 80lb bag covers 0.44 cu yd, 60lb covers 0.33 cu yd, and 40lb covers 0.22 cu yd. Always round up and add 10% extra.

How to calculate concrete for a slab?

Measure length, width, and thickness of your slab. Convert to consistent units (all feet or all meters). Multiply these three dimensions to get volume. Add 10% waste factor for material ordering.

How much concrete will I need calculator?

Our free calculator provides instant results for any rectangular slab. Simply enter your dimensions, and it calculates volume, bags needed, and total cost automatically. Works for both imperial and metric measurements.

How do you calculate yards of concrete?

To calculate concrete yards: (Length ft × Width ft × Depth ft) ÷ 27 = Cubic Yards. For depth in inches, convert to feet first by dividing by 12. Example: 12ft × 12ft × 4in = 12 × 12 × 0.33 ÷ 27 = 1.78 cubic yards.

What thickness should my concrete slab be?

Standard thicknesses: Sidewalks - 4 inches, Driveways - 4-6 inches, Garage floors - 4-6 inches, Basement floors - 4-8 inches. Thicker slabs provide more durability but require more concrete.

Should I include a waste factor?

Yes, always include 10-15% waste factor when ordering concrete. This accounts for spillage, over-excavation, and measurement variations. Our calculator automatically includes 10% waste factor in all calculations.

Can I use this for non-rectangular footings?

For irregular shapes, break them into rectangular sections and calculate each separately, then add the volumes together. For circular slabs, use our Circular Calculator tool available in the sidebar menu.

How accurate is this calculator for cost estimation?

Our calculator provides highly accurate cost estimates based on current market prices. The calculator uses real-time pricing data and factors in regional cost variations to deliver precise cost calculations for your concrete projects.

Can this calculator help me save money on concrete costs?

Yes! Our smart calculator compares different bag sizes and shows cost-per-unit breakdowns to help you identify the most cost-effective purchasing options. The calculator also prevents over-ordering by providing accurate calculations.

What factors affect concrete cost in the calculator?

The calculator considers multiple cost factors including bag sizes, regional pricing, quantity discounts, and delivery costs. Geographic location significantly impacts concrete cost, and our calculator adjusts pricing automatically.

How does the calculator compare costs between bag sizes?

Our calculator analyzes cost-per-cubic-yard for each bag size option, showing you the total project cost breakdown. The calculator highlights the most economical choice by comparing unit costs.

Is this calculator suitable for commercial cost estimating?

While our calculator provides professional-grade calculations suitable for many commercial projects, larger commercial cost estimates may require additional factors like labor costs and equipment costs.

Sonotube Concrete Calculator

Circular Footing Calculator

Calculate concrete volume, bags needed, and cost for round post holes and Sonotube footings. Supports multiple footings calculation

Diameter (in)

Depth (in)

Number of Footings

Enter total number of footings needed

Per Footing Volume

0 cu yd

Total Volume Needed

0 cu yd

3D Shape Preview

Why Choose Our Sonotube Concrete Calculator?

Professional sonotube concrete calculator for piers, round footings, and concrete tubes. Calculate bags needed for 8-14 inch sonotubes with accurate volume estimates.

Sonotube Calculator

Calculate concrete for sonotubes, concrete tubes, and round forms. Supports 8", 10", 12", and 14" diameter tubes.

Pier Concrete Volume

Accurate concrete volume for piers, round footings, and cylindrical forms using πr²h formula for circular calculations.

Sonotube Bag Calculator

Calculate bags needed for sonotubes. Shows 40lb, 60lb, and 80lb bag quantities for your tube diameter and depth.

Concrete Pier Calculator

Calculate concrete for deck piers, foundation piers, and support columns with imperial or metric measurements.

Tube Cost Estimator

Estimate concrete cost for sonotubes and piers. Enter price per bag or cubic yard for instant budget planning.

Free & Easy to Use

No registration needed. Free sonotube concrete calculator for piers, tubes, and round footings with instant results.

How to Calculate Concrete for Sonotubes & Piers

Follow these steps to calculate concrete for sonotubes, piers, and round footings with accurate volume and bag estimates.

Measure Sonotube Diameter & Depth

Measure the diameter of your sonotube or pier (8", 10", 12", or 14") and the depth/height needed for your foundation.

Tip: Common sonotube sizes are 8", 10", and 12" diameter. Measure depth from bottom of footing to grade level.

Enter Diameter & Depth

Input sonotube diameter and depth into the calculator. Select imperial (inches/feet) or metric (cm/meters) units.

Note: Calculator uses circular volume formula (πr²h) for accurate pier concrete calculations.

Review Sonotube Volume & Bags

See concrete volume in cubic yards and bags needed (40lb, 60lb, 80lb) for your sonotube or pier instantly.

Important: For multiple tubes, multiply results by number of piers needed for your project.

Estimate Sonotube Concrete Cost

Enter concrete price per bag or cubic yard to get instant cost estimate for your pier or sonotube project.

Pro Tip: For small projects (<1 cu yd), bags are often more economical than ready-mix delivery.

Sonotube Concrete Formula

Circular Volume Formula:

Volume = π × r² × h

Imperial Calculation:


                        Volume (cu yd) = (3.14 × (Diameter in ÷ 2)² × Depth in) ÷ 46656

Metric Calculation:


                        Volume (cu m) = 3.14 × (Diameter cm ÷ 2)² × Depth cm ÷ 1000000

Common Sonotube Sizes:

• 8" diameter: Deck posts, light structures
• 10" diameter: Standard deck piers, shed foundations
• 12" diameter: Heavy-duty piers, building columns
• 14" diameter: Large structural supports, heavy loads

Frequently Asked Questions About Sonotube Calculators

Common questions about sonotube concrete calculations, pier bag requirements, tube volume, and sonotube project cost estimation.

How much concrete for a sonotube?

Calculate sonotube concrete using πr²h formula. A 12" diameter × 4 ft deep sonotube needs 0.35 cubic yards (9.5 bags of 80lb concrete). Enter diameter and depth in our sonotube calculator for instant results with multiple tube quantities.

What is a sonotube concrete calculator?

A sonotube concrete calculator computes volume and bags needed for circular concrete forms (sonotubes). It uses circular volume formula to calculate concrete for piers, round footings, and tube forms from 8" to 14" diameter.

How many bags of concrete for sonotube?

Depends on tube size. 10" diameter × 3 ft deep needs about 6 bags (80lb). 12" × 4 ft needs 9-10 bags. Use sonotube bag calculator to get exact 40lb, 60lb, and 80lb bag quantities for your specific diameter and depth.

How to calculate concrete pier volume?

Use circular formula: Volume = π × r² × h. For 12" diameter pier: radius=6", so π × 6² × depth (inches) ÷ 46656 = cubic yards. Our pier calculator automatically computes volume for any diameter from 8" to 14" with accurate circular calculations.

What sizes do sonotubes come in?

Common sonotube diameters: 6", 8", 10", 12", 14", 16", 18", 20", 24". Standard depths: 2-12 feet. Most popular for residential: 8", 10", 12" diameter × 3-4 ft deep for deck piers and foundation supports.

How much does a sonotube cost?

Sonotube costs $8-40 per tube depending on size. 8"×4 ft: $8-12, 10"×4 ft: $12-18, 12"×4 ft: $18-25. Plus concrete: 8-10 bags of 80lb mix per 12" tube. Total project cost: tube + concrete + rebar typically $40-80 per pier.

How deep should a sonotube be?

Sonotube depth depends on frost line and load. Minimum: 36-48 inches below grade (below frost line). Deck piers typically 3-4 ft deep. Building piers: 4-6 ft. Always check local building codes for frost depth requirements in your region.

How to fill a sonotube with concrete?

Mix concrete to 4-5 inch slump, pour in 12-18" lifts, consolidate with vibrator or rod to remove air pockets. For deep tubes, use chute or pump. Fill to 2-3 inches below top, smooth finish. Let cure 24-48 hours before removing tube form.

Do I need rebar in sonotubes?

Yes, most codes require rebar in concrete piers. Typical: 3-4 vertical #4 rebar bars for 10-12" tubes, extending from footing base to 2" from top. Add horizontal ties every 16-24". Rebar prevents cracking and provides structural strength.

What is the difference between sonotube and concrete tube?

Sonotube is a brand name for fiber concrete forms. "Concrete tube" is generic term for any round cardboard form. Sonotube is the most popular brand. Both work the same: disposable round forms for pouring concrete piers and columns.

How long before I can remove sonotube?

Wait 24-48 hours minimum before removing sonotube forms. For best results, wait 3-7 days to ensure concrete reaches sufficient strength. Peel away cardboard form carefully from top to bottom. Concrete continues curing for 28 days to full strength.

Can I reuse sonotubes?

No, sonotubes are single-use disposable forms. The cardboard absorbs moisture from concrete and must be peeled away after curing. For multiple piers, purchase one tube per pier. Some contractors use plastic or steel reusable forms as alternative.

How many sonotubes do I need for a deck?

Depends on deck size and span. Typical 12×16 ft deck: 6-9 piers at 6-8 ft spacing. Use 10-12" diameter tubes. Multiply single tube concrete volume by number of piers. Example: 9 piers × 0.25 cu yd each = 2.25 cu yd total (about 70 bags of 80lb).

What PSI concrete for sonotubes?

Use 3000-4000 PSI concrete for sonotube piers. 3000 PSI: residential deck piers, light structures. 4000 PSI: heavy loads, building foundations, cold climates. Higher PSI provides better strength and freeze-thaw resistance. Check local building codes for requirements.

How to calculate sonotube concrete cost?

Calculate volume in cubic yards, multiply by concrete price. Example: 12" tube × 4 ft = 0.35 cu yd. At $6.50/bag (80lb): 0.35 ÷ 0.0148 = 9.5 bags × $6.50 = $62. Add tube cost ($20) + rebar ($10) = $92 total per pier.

Concrete Calculation Guide

Essential knowledge for accurate concrete calculations, measurement tips, and project planning guidelines.

Sonotube Measurement

• Measure tube diameter across center (8", 10", 12", 14")
• Measure depth from bottom of footing to grade
• Account for 2-3" below tube for footing pad
• Check local frost line depth requirements
• Standard depths: 3-4 ft for decks, 4-6 ft for buildings
• Count total number of piers needed for project

Pier Specifications

Common Sonotube Sizes:

• 8" diameter: Light loads, small decks
• 10" diameter: Standard deck piers
• 12" diameter: Heavy-duty structures

Rebar Requirements:

• 8-10" tubes: 3 vertical #4 rebar
• 12" tubes: 4 vertical #4 rebar
• Horizontal ties every 16-24 inches

Sonotube Cost Guide

8" × 4 ft tube:

~5 bags (80lb) + $10 tube = $40-50/pier

10" × 4 ft tube:

~7 bags (80lb) + $15 tube = $55-70/pier

12" × 4 ft tube:

~10 bags (80lb) + $20 tube = $80-100/pier

Project Planning

• Order 10-15% extra concrete
• Schedule delivery for early morning
• Have tools ready before mixing
• Check weather forecast (no rain)
• Prepare sub-base and forms first
• Plan for immediate use of mixed concrete

Cost Considerations

• Bagged: $6-8 per 80lb bag
• Ready-mix: $100-150 per cubic yard
• Delivery fees: $50-100 typical
• Minimum orders may apply
• Weekend/overtime rates higher
• Compare total project cost, not just per-unit

Quality Tips

• Use proper water-to-cement ratio
• Avoid adding excess water
• Consolidate concrete to remove air
• Level and smooth surface properly
• Allow adequate curing time
• Protect from temperature extremes

Quick Reference: Common Sonotube Sizes

Common sonotube sizes showing concrete volume needed for different diameter tubes at various depths
Sonotube Size	3 ft Deep (cu yd)	4 ft Deep (cu yd)	80lb Bags (4 ft)
8" diameter	0.13 cu yd	0.17 cu yd	5 bags
10" diameter	0.20 cu yd	0.27 cu yd	7 bags
12" diameter	0.29 cu yd	0.39 cu yd	10 bags
14" diameter	0.40 cu yd	0.53 cu yd	14 bags
16" diameter	0.52 cu yd	0.70 cu yd	18 bags

* Bag counts are estimates for 80lb bags. Add tube cost ($10-25) and rebar ($8-15) per pier for total cost.